Rockets have been used for many years to launch human and non-human payloads into orbit. Such rockets delivered the first humans to space and to the moon, and have launched countless satellites into the Earth's orbit and beyond. Such rockets are used to propel unmanned space probes and more recently to deliver structures, supplies, and personnel to the orbiting International Space Station.
One characteristic of many existing rocket engines is the limited ability to control the thrust produced by such engines. While this is not typically an issue for single-purpose rocket stages that propel a payload outside the Earth's atmosphere, such features can limit the functionality of rocket engines that provide more versatile functions. Accordingly, there remains a need for rocket engines having an increased level of controllability.